blackGradients.
The gradient prior is also used as an auxiliary loss for inpainting in [1]}.
As in [1]}, we use Sobel filters to extract ground truth RGB gradients \(\mathbf {\hat{P}}_{g}\)  in two directions, i.e., horizontal and vertical gradient maps.
Gradient priors \(\mathbf {\tilde{P}}_{g}\)  are optimized by \(L_1\)  loss with edge regularization as [1]}:
\(\mathcal {L}_{grad}=\beta _1\mathbb {E}[||\mathbf {\tilde{P}}_{g}-\mathbf {\hat{P}}_{g}||_1]+\beta _2\mathbb {E}[(g*\mathbf {C})\odot ||\mathbf {\tilde{P}}_{g}-\mathbf {\hat{P}}_{g}||_1],\) 
